Primor had been named by Germany's Sueddeutsche Zeitung as the source of Piech's information in early 2015 that trouble could be brewing for Volkswagen, which later that year was forced to admit it deliberately cheated the tests.
He said he had got to know Piech while he was ambassador in Berlin during the 1990s. Piech had approached Primor, a promoter of German-Israeli dialogue, because he wanted to support his university projects, Primor said.
"I spoke with Mr Piech only concerning this university project," he told Reuters by telephone.
German media have reported in the past days that then-chairman Piech raised the issue with then-chief executive Martin Winterkorn and key members of the supervisory board in early 2015, six months before it became a public scandal.
Volkswagen signalled on Wednesday it could take legal action against Piech, and said it "emphatically denied" the allegation that supervisory board members knew about the problem in advance.
(Reporting by Georgina Prodhan; Editing by Ludwig Burger)
